The present invention relates to a yarn texturizing nozzle of the type which includes an inlet portion where the yarn is subjected to a jet of heated treatment fluid which serves to heat the yarn and advance the yarn into a stuffer box which is mounted immediately downstream of the inlet portion.
In the production of man made fibers at high operating speeds of, for example, 2,000 m/min and above, the threading of the yarn into an advance and texturizing nozzle of the described type presents a significant problem, and it is conventional to draw the yarn into the nozzle by a suction gun, which is time consuming and requires special equipment. As a result, various attempts have been made to simplify and shorten the time of the threading operation, as illustrated for example from U.S. Pat. No. 4,416,041 and published EPO Application No. 0065726.
The methods and apparatus described in the above prior art references relate to threading nozzles wherein a yarn or an auxiliary yarn is sucked into a nozzle. In methods and apparatus operating at very high yarn speeds, such sucking of the yarn into the nozzle is not possible, inasmuch as the nozzle geometry does not permit suction currents at high speeds. In addition, nozzles have previously been constructed which are divided along an axial plane of the yarn passage, so that the advancing yarn can be threaded into the nozzle in a direction transverse to its advance, note for example U.S. Patent No. 3,854,177. However, this prior construction has impaired the geometry of the yarn passage and the conduit for the treatment fluid, and as a result less than satisfactory texturizing results are achieved.
Other nozzles which can be opened by a hinged construction are illustrated in British Pat. No. 872,234 and U.S. Pat. Nos. 2,938,257 and 3,199,339. These nozzles are directed to the formation of loops and bows in the yarn so as to increase its bulk.
Finally, U.S. Pat. No. 4,453,298 illustrates a texturizing nozzle having a texturizing chamber which includes an annular conduit surrounding the yarn passage, and which includes several ducts which are inclined at an acute angle with respect to the yarn passageway, and which communicate with the yarn passageway in a mixing chamber. This nozzle is divided along an axial plane, and can be opened for laterally inserting the yarn into the yarn passageway. A disadvantage in this nozzle construction resides in the fact that the annular conduit is formed into the circumference of an inserted body, which must similarly be divided along an axial plane for the purpose of opening the nozzle, and which requires a high degree of accuracy in the manufacture of the inserted body, and a precisely fitting attachment of the two halves of the inserted body to the corresponding parts of the nozzle block.
It is an object of the present invention to provide a yarn texturizing nozzle which avoids the above noted disadvantages of the prior art, and which provides for the simple and rapid threadup of the yarn into the nozzle without impairing its efficiency. It is also an object of the present invention to provide a yarn texturizing nozzle of the described type wherein the heated treatment fluid enters into the yarn passageway from an annular distributor duct without using an inserted body which is divided in an axial plane.
It is a further object of the present invention to provide an optimum design for the inlet portion of a texturizing nozzle as well as the stuffer box portion, and which represents an improvement of texturizing nozzles shown in published European Patent Application Nos. 108,205, 123,072, 26,360, and 110,359. The texturizing nozzles illustrated in these applications consist of two halves which are tightly held against each other during operation. It is therefore necessary that the texturizing nozzles have the same rigidity over their entire length. This is in contrast to the necessity to provide the stuffer box with slots, holes or similar openings by which the heated treatment fluid may escape from the stuffer box without undue hinderance or throttling.